1. Field of the Invention
The present invention relates to a cooling apparatus.
2. Description of the Related Art
An electronic device, such as a notebook PC, produces a large amount of heat at a CPU and the like inside a case thereof. This makes it important to take measures against the heat. One common measure against the heat is to install a blower fan inside the case to discharge the heat. Meanwhile, when the blower fan is installed inside the case, the blower fan itself also absorbs the heat inside the case, and an operation environment of the blower fan may deteriorate.
Accordingly, a fan unit disclosed in JP-A 2004-316505 includes a heat dissipating layer arranged on an outside surface of an impeller, and a heat generated in a rotating shaft is dissipated therethrough.
Here, in a common centrifugal fan, an air current is directed from one axial side (an inlet side) to a radially outer side (an outlet side) by circumferential rotation of blades. At this time, an air between adjacent ones of the blades is directed radially from the one axial side by the rotation of the blades, and the air is therefore unlikely to flow to an opposite axial side. This makes it difficult for a heat on the opposite axial side inside the case to be discharged, and the heat may stay inside the centrifugal fan.